Arrangement and method for the demand-based control of cooling / lubricating oil flows and their flow temperatures in electric traction drive

Abstract

Arrangement (1) for the demand-based control of the supply temperatures of cooling / lubricating oil flows in the electric traction drive with an electrically controllable motor-pump unit (21) and a hydraulic unit (15), wherein the motor-pump unit (21) can be controlled in two directions of rotation, namely in a first direction of rotation and in a second direction of rotation opposite to the first direction of rotation, and wherein a first pressure level and a second pressure level that is higher than the first pressure level can be set on the motor-pump unit (21) by regulating the speed in the first direction of rotation or the second direction of rotation, and wherein the motor-pump unit (21) is connected via the hydraulic unit (15) to a plurality of fluid outlets for a first, a second and a third partial volume flow (20', 20'', 20'''), which fluid outlets are arranged for cooling and / or heating and / or lubricating at least on the stator (5) of an electric drive machine (2),and / or the rotor (3) of the electric drive machine (2) and / or the transmission (10), wherein the arrangement (1) comprises a heat exchanger (14), and wherein the first partial volume flow (20') is not connected to the heat exchanger (14), and wherein the direction of rotation and the pressure level of the motor-pump unit (21) can be adjusted via an electrical control unit and three different operating modes can be set depending on the direction of rotation and the pressure level.

Description

[0001] The invention relates to an arrangement and a method for the demand-based control of cooling / lubricating oil flows and their flow temperatures in electric traction drives with an electrically controllable motor-pump unit and a hydraulic arrangement, wherein the motor-pump unit can be controlled in both directions of rotation, and wherein the motor-pump unit is connected via a heat exchanger to a plurality of fluid outlets which are connected for cooling and / or heating and / or lubrication at least to the stator of an electric machine, the rotor of an electric machine and to the transmission. State of the art

[0002] Electric traction drives essentially consist of an electric motor, an inverter, and a reduction gear. The maximum performance, service life, and efficiency of these components are largely determined by the selected cooling concept. The trend toward ever higher performance in the same space and the increasing integration density inevitably require improvements in cooling and thermal management.

[0003] Powerful, high-energy-density electric drive systems are generally equipped with an electrically driven oil pump and an oil-water heat exchanger for cooling purposes. Oil pumps driven by brushless direct current (BLDC) motors are typically used. The preferred pump type is a rotary positive displacement pump in the form of annular gear pumps or gerotor pumps.

[0004] The flow rate provided by the electric oil pump is primarily used to cool the temperature-critical active components (stator and / or rotor) of the electric machine as needed. The electrically operated oil pump is switched on and off as needed and / or operated at a speed-controlled rate.

[0005] Cooling and lubrication of the transmission components is usually passive, utilizing the pumping action of the differential spur gear or an intermediate shaft spur gear in combination with a suitable housing that acts as an oil guide. This results in a limited pumping action that is dependent on the vehicle speed or gear speed, and associated hydrodynamic losses (splashing losses), which are highly dependent on the speed and oil temperature.

[0006] An increase in the overall efficiency of the electric drive system can be achieved by actively supplying the transmission with a cooling / lubricating oil volume flow provided by the electric oil pump (dry sump lubrication).

[0007] The disadvantage here is that when both the active components (stator and rotor) of the electric motor and the gearbox are actively supplied by a cooling / lubricating oil volume flow provided by the electric oil pump, the fluid supply temperature of the cooling / lubricating oil flows flowing into the "gearbox" and "electric motor" subsystems cannot be controlled independently of one another, but is determined by the heat exchanger outlet temperature. In general, for reasons of high thermal availability, the aim is to keep the cooling oil supply temperature low for cooling the temperature-critical active components (stator and / or rotor) of the electric drive motor. On the other hand, the supply temperature of the partial volume flow used to cool and lubricate the components of the reduction gear and differential can be raised to a higher supply temperature to reduce viscous friction losses.

[0008] To solve this problem, WO 2023 / 133 200 A1 discloses a vehicle drive unit with an electric motor and a transmission as subcomponents. Separate cooling lubricant circuits with correspondingly adapted lubricant compositions and properties are provided for both subsystems. A separate pump, filter, and cooler are required for each cooling lubricant circuit.

[0009] The object of the invention is to enable an improved, demand-based provision of the cooling oil flows to the rotor shaft and stator of the electric motor as well as to the transmission components, whereby the electric drive system is to be cost-effective with improved overall efficiency and optimized with regard to the number of components and installation space.

[0010] This problem is solved by claim 1.

[0011] The arrangement according to the invention for the demand-based control of cooling / lubricating oil flows in electric traction drives makes it possible to adjust the fluid flow temperatures of the partial volume flows to the transmission components and to the temperature-critical active components of the electric drive machine (stator and / or rotor) in a simple manner and with few hydraulic components.

[0012] The existing motor-pump unit is expanded with simple and cost-effective hydraulic valves and shut-off valves, enabling bidirectional pump operation. This allows for different flow distributions—defined by hydraulic resistance control—to be realized in clockwise and counterclockwise rotation of the pump.

[0013] By means of the arrangement according to the invention, which comprises an oil pump installed in the transmission, which is connected to a hydraulic unit, and has a heat exchanger, the lubricating coolant, which is preferably an oil, can be guided as an oil stream either through the heat exchanger or directly into the transmission or the temperature-critical active components (stator and / or rotor).

[0014] This means that the most efficient state can always be selected depending on the vehicle operating mode by using an appropriate operating strategy for the electric oil pump.

[0015] According to the invention, active cooling of temperature-critical active components, such as the stator and / or rotor of the electric drive unit (electric motor), is possible. Furthermore, active cooling and lubrication of the transmission is possible, or, in another operating mode, passive lubrication of the transmission through splashing.

[0016] Non-cooled oil can be pumped into the gearbox because it is located on the high-temperature side.

[0017] The partial volume flows can be preset using orifices.

[0018] The hydraulically switchable valve is a hydraulically operated 3 / 2-way valve.

[0019] The arrangement can be implemented in a robust design by using simple hydraulic shut-off valves and intelligent operating strategies.

[0020] In a further development according to the invention, the various operating modes can be implemented by simple check valves and spring check valves, so that a hydraulically actuated 3 / 2-way valve can be dispensed with.

[0021] To achieve different flow temperatures for the gearbox on the high-temperature side and the electric motor with its active components, the rotor and stator, on the low-temperature side, only one motor-pump unit and one heat exchanger are required. This is particularly advantageous in terms of cost and installation space.

[0022] The problem is also solved with a method for the demand-based distribution of cooling / lubricating oil flows in the electric traction drive.

[0023] It is advantageous to set different operating modes in order to adjust the flow temperatures of the respective partial volume flows at the fluid outlets.

[0024] Three different operating modes can be set: operation of the motor-pump unit in direction of rotation A or direction of rotation B with different pressure levels.

[0025] The solution according to the invention results in the following advantages: The invention allows the demand-based control of the flow temperature of partial volume flows to increase the efficiency and / or thermal availability of electric drive systems with fully or partially oil-cooled electric drive motors.

[0026] The hydraulically controlled valves allow precise control of the partial volume flows without additional electrical energy requirements.

[0027] The possibility of adjusting the partial volume flows via software provides a high level of flexibility.

[0028] By combining it with intelligent, self-learning functional software, the desired maximum in terms of efficiency and / or thermal availability can be achieved - depending on the operating mode. Description of the characters

[0029] It shows: Fig. 1 a schematic representation of the cooling lubricant circuit according to the invention, with adjustable fluid flow temperature of the partial volume flows to the gearbox and to the temperature-critical active components of the electric drive machine (stator and / or rotor), Fig. 2 a hydraulic circuit diagram of the arrangement according to the invention in a first embodiment with a 3 / 2 way valve, Fig. 3 a hydraulic circuit diagram of the arrangement according to the invention in a second embodiment with two separate oil sumps and a 3 / 2-way valve, Fig. 4 a hydraulic circuit diagram of the arrangement according to the invention in a third embodiment with two separate oil sumps, Fig. 5 a signal flow diagram of the method for the demand-based distribution of cooling / lubricating oil flows in an electric traction drive according to the first embodiment Fig. 6 shows a profile of the volume flow of the first embodiment in a first realizable operating mode, Fig. 7 shows a profile of the volume flow of the first embodiment in a second realizable operating mode, Fig. 8 shows a profile of the volume flow of the first embodiment in a third realizable operating mode, Fig. 9 shows a profile of the volume flow of the third embodiment in a first realizable operating mode, Fig. 10 shows a profile of the volume flow of the third embodiment in a second feasible operating mode; and Fig. 11 shows a profile of the volume flow of the third embodiment in a third realizable operating mode.

[0030] The Fig. Figure 1 shows a schematic representation of the cooling lubricant circuit of the arrangement 1 for the demand-based control of cooling / lubricating oil flows in the electric traction drive. The electric traction drive comprises an electric drive motor 2 and a transmission 10 as components to be lubricated and / or cooled, integrated into the cooling lubricant circuit. Oil is preferably used as a hydraulic fluid as the cooling lubricant.

[0031] As can be seen from the illustration, the cooling lubricant circuit has a low temperature level (temperature level 2) on the left side on the side of the electric drive motor 2 and a high temperature level (temperature level 1) on the right side on the side of the gearbox 10. The division into low temperature level and high temperature level is indicated by the dashed vertical line. To achieve these different fluid supply temperatures, the arrangement 1 according to the invention can be used to adjust the corresponding fluid supply temperatures via a first partial volume flow to the gearbox and via a second and third partial volume flow to the temperature-critical active components of the electric drive motor 2. This will be explained later using the hydraulic circuit diagrams of the Fig. 2, Fig. 3 and Fig. 4, and 6 - 11 are described in more detail.

[0032] The electric drive motor 2 has a rotor 3 with a rotor shaft 4, which rotates about its axis of rotation D in a stator 5. The stator 5 has, as is customary, a stator core with stator windings that project axially beyond the stator core on both ends as so-called winding heads. Rotor 3 and stator 5 with winding heads form the aforementioned temperature-critical active components of the electric drive components, which can be cooled via the second and third partial volume flows. An oil sump 6 is assigned to the electric drive motor 2.

[0033] The rotor shaft 4 is connected as an output shaft to an intermediate shaft 8 via a gear pair, and the intermediate shaft 8 is connected via another gear pair to the transmission 10, which is designed as a differential. The transmission 10, designed as a differential, has an output shaft 11. An oil sump 12 is associated with the transmission 10.

[0034] As it continues from the Fig. 1, a heat exchanger 14 and a hydraulic unit 15 which is in fluid communication with the heat exchanger via an inlet and outlet line 14a and 14b and which comprises hydraulic valves, as well as a motor-pump unit 21 are connected on the low-temperature side.

[0035] Starting from the hydraulic unit 15, a fluid line 16 to the transmission 10 and a fluid line 17 to the electric drive motor 2 are provided. The fluid line 16 is assigned to the first partial volume flow 20' at the high temperature level for cooling / lubricating the transmission GBX,10. The fluid line 17 is assigned to the second and third partial volume flows at the low temperature level. The division of the fluid line 17 into the second and third partial volume flows 20'' and 20''' is evident from the illustration of the Fig. 1 is not visible. As described in more detail below, the second partial volume flow 20'' serves to lubricate and cool the rotor and the third partial volume flow 20''' serves to lubricate and cool the winding heads of the stator 5.

[0036] Fig. 2 shows a hydraulic circuit diagram according to the arrangement 1 according to the invention for the demand-based control of partial volume flows 20', 20'', 20''' and the flow temperatures with the hydraulic unit 15, the motor-pump unit 21 and a heat exchanger 14 in a first embodiment.

[0037] The coolant lubrication pump 18 is driven by an electric motor 19, which can rotate in both directions. The two components form the electrically controllable motor-pump unit 21. The clockwise (cw) rotation of the electric motor and pump 18 is referred to as direction of rotation A, while the counterclockwise (ccw) rotation of the electric motor and pump 18 is referred to as direction of rotation B.

[0038] The coolant lubrication pump 18 is connected to an oil sump 27 on the suction and pressure sides via a first check valve 26' and a second check valve 26''. Depending on the direction of rotation of the pump, one of the two check valves 26', 26'' is in an open position and the other in a closed position. The connection to the oil sump 27 is established via a sieve or filter element 28 arranged between them.

[0039] During operation of the pump 18, the entire delivery volume flow provided by the pump 18 is guided via a shuttle valve 31 and a hydraulically controllable switching valve 32 in the form of a spring-loaded 3 / 2-way valve, which is adjustable via a pump pressure applied in a control line 33. In a first Fig. 2, the entire delivery volume flow is fed to the heat exchanger 14 via a fluid line 34. In a second position of the 3 / 2-way valve, the entire delivery volume flow is divided and a first portion is fed to the heat exchanger 14 via the fluid line 34, wherein after the oil has flowed through the heat exchanger 14, the portion of the delivery volume flow can be divided into the second and third partial volume flows 20'' and 20'' between the rotor shaft RW and the stator winding heads WH. In the flow line of the partial volume flow 20'' to the rotor 3, a hydraulically controllable check valve 36 with a bypass line 37 with an orifice is arranged, as well as an orifice 38a in the inlet to the rotor 3, which enables resistance control over a defined flow cross-section.

[0040] The second part of the delivery volume flow is supplied in the second position of the 3 / 2-way valve 32 as the first partial volume flow 20' via the fluid line 16 in which a check valve 39 is installed, as well as an orifice 38b in the inlet to the gearbox GBX,10.

[0041] A flow line 22 with a check valve 23 is provided between the inlet to the stator and the inlet to the gearbox. The check valve 23 blocks the flow direction from the fluid line 16 to the inlet in the direction of rotor 3.

[0042] The motor-pump unit 21 is controlled with regard to the direction of rotation and the pump pressure to be set via an electrical control unit (not shown) connected to a data bus. The control unit is connected to the motor 20 of the motor-pump unit 21 via an electrical line.

[0043] Fig. 3 shows a hydraulic circuit diagram according to the inventive arrangement 1 for the demand-based control of partial volume flows 20', 20'', 20''' with a hydraulic unit 15 and a heat exchanger 14 in a second embodiment. In contrast to the Fig. In the embodiment described in Figure 2, the oil sump 27 with filter element 28 common for both directions of rotation of the motor-pump unit 21 is replaced by a separate oil sump 6, 12 with a filter element 28', 28'' arranged in front of the suction side.

[0044] Accordingly, the oil sump 12 is assigned to the gearbox GBX,10 and the oil sump 6 is assigned to the electric drive motor 2.

[0045] Fig. Figure 4 shows a hydraulic circuit diagram according to the inventive arrangement 1 for the demand-based control of partial volume flows 20', 20'', 20''' with a hydraulic unit 15 and a heat exchanger 14 in a third embodiment. In contrast to the Fig. In the second embodiment shown in Figure 3, the shuttle valve 31 and the hydraulically controllable switching valve 32 arranged downstream in the flow path are omitted. Instead, two further simple check valves 43, 44 are used in the hydraulic circuit diagram.

[0046] Fig. Figure 5 shows, by way of example, a method for the demand-based distribution of cooling / lubricating oil flows and the control of the cooling oil flow temperatures of the partial volume flows in an electric traction drive with an inventive arrangement according to one of the preceding figures. A request for active pump operation of the pump is queried, whereby the active pump operation can be an operating mode in a first direction of rotation A or in a second direction of rotation B.

[0047] The flowchart first asks whether the vehicle is moving. If this question is answered in the affirmative, the winding head limit temperature is checked.

[0048] If the winding head limit temperature is not reached, the query is terminated and no pump operation is necessary.

[0049] However, if the winding overhang limit temperature is reached or exceeded in this question, a query is made as to whether the rotor shaft limit temperature RS of the electric machine has been reached. If this is not the case, a query is made as to whether the gearbox limit temperature has been reached. If this is not the case, pump operation in direction of rotation A is initiated with a pressure level of 1 to achieve the first operating mode. If the limit temperatures (winding overhang and rotor shaft) are both reached or exceeded, a query is made as to whether the gearbox limit temperature has been reached. If the gearbox limit temperature is reached or exceeded, pump operation in direction of rotation A is initiated with a pressure level of 2 to achieve the second operating mode.

[0050] However, if it is determined in this query step that the gearbox limit temperature has not yet been reached. However, as previously described, the winding head and rotor shaft limit temperatures have been reached, then pump operation is initiated in direction of rotation B with pressure level 1 to achieve the third operating mode.

[0051] If the first query in the flowchart shown determines that the vehicle is not moving, a choice is made between active cooling or heating conditioning. If "cooling" is requested in the query, the heat exchanger is activated to achieve "cooling" conditioning. Furthermore, pump operation is initiated in direction A of rotation with pressure level 1 to achieve the first operating mode.

[0052] If no cooling is requested, "heating" is requested after conditioning. If this is requested, the winding heads are energized and pump operation is initiated in direction of rotation A with pressure level 1 to achieve the first operating mode.

[0053] The third operating mode describes an optimized efficiency mode in which warm oil is present in the gearbox and cold oil is present for the stator windings of the electric machine and no oil is pumped into the rotor shaft of the electric machine, thus eliminating churning losses in the rotor shaft.

[0054] By raising the temperature level in the gearbox with warm oil, the oil viscosity is reduced and thus the splash losses and the gear losses are reduced.

[0055] For example, it can be measured that if the temperature in the gearbox is increased by 10°C, the energy required to operate the traction drive is reduced by ~9Wh.

[0056] In the second operating mode, the oil flow in the gearbox, the rotor / stator, and the stator winding heads is cooled, thereby achieving the maximum possible performance of the electric traction drive. In this operating mode, maximum speed and a consistently large amount of energy can be achieved.

[0057] In the first operating mode, only the stator winding heads are cooled; otherwise, the gearbox is allowed to generate splash losses, and rotor cooling is omitted. Moderate driving is possible, especially when starting a vehicle.

[0058] The parameters for the control and switching between the operating modes described above are oil temperature, pump power, power and / or the speed of the electric machine.

[0059] The Fig. 6, Fig. 7 and Fig. 8 show the ones with the Fig. Operating modes that can be realized with the arrangement shown in Figure 3.

[0060] In the Fig. In the first operating mode shown in Figure 6, the volume flow 40 of the cooling lubricant (oil) originating from the oil sump 12 is shown with a dashed line. It can be seen that in the first operating mode, only the partial volume flow 20''' is provided to the stator 5, thereby providing active stator cooling.

[0061] In the first operating mode, the pump 18 of the motor-pump unit 21 is operated at a clockwise pump speed at a first pressure level (low pressure level), whereby the cooling lubricant is sucked in from the oil sump 12 and fed via the shuttle valve and the 3 / 2-way valve in the first position and the flow line 24 through the heat exchanger 14 and then directly to the stator. Due to the low pressure level in the flow lines, the hydraulically controllable shut-off valve 36 remains in the shut-off position. The rotor is therefore not cooled.

[0062] Cooling and lubrication in the GBX, 10 gearbox is implemented passively, with oil being pumped as a cooling lubricant from the gears of the gearbox into a reservoir by splashing and then distributed via channels in the gearbox.

[0063] In the Fig. In the second operating mode shown in Figure 7, the volume flow 41 of the cooling lubricant (oil) originating from the oil sump is shown with a dashed line. It can be seen that in the second operating mode, all partial volume flows 20', 20'', 20''' are provided to the gearbox GBX, 10, the rotor 3, and the stator 5, thereby actively cooling the temperature-critical active components stator 5 and rotor 3. In addition, lubrication and cooling of the gearbox 10 are also actively implemented.

[0064] In the second operating mode, the pump 18 of the motor-pump unit 21 is operated at a clockwise pump speed at a second pressure level (high pressure level), whereby the cooling lubricant (oil) is sucked in from the oil sump 12 and guided through the heat exchanger 14 via the shuttle valve 31 and the 3 / 2-way valve 32 in the first position and the flow line 24. After the heat exchanger 14, the volume flow 41 is divided into the three partial volume flows 20', 20'', 20'''. Due to the high pressure level in the flow lines, the hydraulically controllable shut-off valve 36 is unlocked and a portion of the volume flow is fed to the rotor via the orifice 38a, and a portion of the volume flow is fed to the gearbox 10 via the fluid line 22, the check valve 23, and the orifice 38b. All partial volume flows have the same flow temperature in the second operating mode.

[0065] In the Fig. In the third operating mode shown in Figure 8, the volume flow 42 of the cooling lubricant (oil) originating from the oil sump is shown with a dashed line. It can be seen that in the third operating mode, the partial volume flows 20' and 20''' are provided to the GBX gearbox 10 and the stator 5. The partial volume flows 20' and 20''' have different flow temperatures, since the partial volume flow 20' is not routed through the heat exchanger 14 for cooling.

[0066] Oil is actively pumped into the gearbox 10 for lubrication, but does not first flow through the heat exchanger 14. Cooling of the stator 5 is active, while the rotor 3 is not cooled.

[0067] In the third operating mode, the pump 18 of the motor-pump unit 21 is operated at a counterclockwise pump speed at a first pressure level (low pressure level), whereby the cooling lubricant (oil) is sucked in from the oil sump 6. However, the oil can also be sucked in from a connected oil sump 27, as shown in Figure 2.

[0068] The oil is then directed via shuttle valve 31 in the second position and 3 / 2-way valve 32 in the second position. When the pump is operating at a counterclockwise pump speed, the 3 / 2-way valve is moved to the second position via control line 33 and the prevailing pressure. In this second position of the 3 / 2-way valve 32, the volume flow 42 is divided into a portion that is guided via flow line 24 through heat exchanger 14 and then fed directly to stator 5. Due to the low pressure level in the flow lines, the hydraulically controllable shut-off valve 36 remains in the shut-off position. The rotor 3 is therefore not cooled.

[0069] A second portion of the volume flow 42 is conveyed via the 3 / 2-way valve directly into the fluid line 16 as partial volume flow 10' into the gearbox 10; this portion of the volume flow does not flow through the heat exchanger 14, is not cooled and therefore has a higher flow temperature.

[0070] The Fig. 9, Fig. 10 and Fig. 11 show the ones with the Fig. Operating modes that can be realized with the arrangement shown in Figure 4.

[0071] With this arrangement and the corresponding method, the cooling lubricant can also either be passed through the heat exchanger or be delivered directly to the transmission 10 or the temperature-critical active components of the electric machine 2. In contrast to the previously described arrangement and method according to the first and second embodiments, the three different operating modes are implemented by simple check valves 43, 44 and spring check valves 36. The shuttle valve 31 and the 3 / 2-way valve 32 are omitted.

[0072] In the Fig. In the first operating mode shown in Figure 9, the volume flow 40 of the cooling lubricant (oil) originating from the oil sump is shown with a dashed line. It can be seen that in the first operating mode, only the partial volume flow 20''' is provided to the stator 5, thereby providing active stator cooling.

[0073] In the first operating mode, the pump 18 of the motor-pump unit 21 is operated at a clockwise pump speed at a first pressure level (low pressure level), whereby the cooling lubricant is sucked in from the oil sump and fed via the flow line 24 through the heat exchanger 14 and then directly to the stator. Due to the low pressure level in the flow lines, the hydraulically controllable shut-off valve 36 remains in the shut-off position. The rotor is therefore not cooled.

[0074] The flow line 48, which is a connection between the flow line 24 and the fluid line 16, is blocked by the check valve 44 in the direction of the gearbox inlet.

[0075] Cooling and lubrication in the GBX, 10 gearbox is implemented passively, with oil being pumped as a cooling lubricant from the gears of the gearbox into a reservoir by splashing and then distributed via channels in the gearbox.

[0076] In the Fig. In the second operating mode shown in Figure 10, the volume flow 41 of the cooling lubricant (oil) originating from the oil sump 12 is shown with a dashed line. It can be seen that in the second operating mode, all partial volume flows 20', 20'', 20''' are provided to the GBX gearbox 10, the rotor 3, and the stator 5, thereby actively cooling the temperature-critical active components of the stator and rotor. In addition, lubrication and cooling are also actively implemented by the gearbox.

[0077] In the second operating mode, the pump 18 of the motor-pump unit 21 is operated at a clockwise pump speed at a second pressure level (high pressure level), whereby the cooling lubricant (oil) is sucked in from the oil sump 12 and guided through the heat exchanger 14 via the flow line 24. Downstream of the heat exchanger 14, the volume flow 41 is divided into the three partial volume flows 20', 20'', 20'''. Due to the high pressure level in the flow lines, the hydraulically controllable shut-off valve 36 is unlocked, and a portion of the volume flow is fed to the stator via the orifice 38a, and a portion of the volume flow is fed to the gearbox via the check valve and the orifice 38b. In the second operating mode, all partial volume flows have the same flow temperature, which is required to cool the components.

[0078] In the Fig.In the third operating mode shown in Figure 11, the volume flow 42 of the cooling lubricant (oil) originating from the oil sump 6 is shown with a dashed line. It can be seen that in the third operating mode, the partial volume flows 20' and 20''' are provided to the GBX gearbox 10 and the stator 5. The partial volume flows 20' and 20''' have different flow temperatures, since the partial volume flow 20' is not routed through the heat exchanger 14 for cooling.

[0079] Oil is actively pumped into the gearbox 10 for lubrication, but does not first flow through the heat exchanger 14. Cooling of the stator 5 is active, while the rotor 3 is not cooled.

[0080] In the third operating mode, the pump 18 of the motor-pump unit 21 is operated at a counterclockwise pump speed at a first pressure level (low pressure level), whereby the cooling lubricant (oil) is sucked in from the oil sump 6. However, the oil can also be sucked in from a connected oil sump 27, as shown in Figure 2.

[0081] The volume flow 42 is then divided. A first portion is directed via the flow line 48 and the check valve 44 into the flow line 24 and then through the heat exchanger 14, before being fed directly to the stator 5. Due to the low pressure level in the flow lines, the hydraulically controllable shut-off valve 36 remains in the shut-off position. The rotor 3 is therefore not cooled.

[0082] A second portion of the volume flow 42 is conveyed directly into the fluid line 16 into the gearbox 10; this portion of the volume flow does not flow through the heat exchanger 14, is not cooled and therefore has a higher flow temperature. Reference symbol 1 arrangement 2 electric drive motors 3 Rotor 4 Rotor shaft 5 Stator 6 Oil sump 8 Intermediate shaft 10 GBX, gearbox 11 Output shaft 12 Oil sump 14 heat exchangers 14a inflow line 14b Drain line 15 Hydraulic unit 16 Fluid line 17 Fluid line 18 Cooling lubricant pump 19 Electric motor 20' first partial volume flow 20'' second partial volume flow 20''' third partial volume flow 21 Motor-pump unit 22 Fluid line 23 Check valve 24 Flow line 26' check valve 26'' check valve 27 Oil sump 28 filter element 31 shuttle valve 32 hydraulically controlled switching valve 33 Control line 34 Fluid line 36 check valve 37 Bypass line 38a aperture 39 Check valve 38b aperture 40 volume flow 41 Volume flow 42 Volume flow 43 Check valve 44 Check valve 48 Flow line WH stator winding heads QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2023 / 133 200 A1

[0008]

Claims

[1] Arrangement (1) for the demand-based control of the flow temperatures of cooling / lubricating oil flows in the electric traction drive with an electrically controllable motor-pump unit (21) and a hydraulic unit (15), wherein the motor-pump unit (21) can be controlled in two directions of rotation, namely in a first direction of rotation and in a second direction of rotation opposite to the first direction of rotation, and wherein a first pressure level and a second pressure level higher than the first pressure level can be set on the motor-pump unit (21) by regulating the speed in the first direction of rotation or the second direction of rotation, and wherein the motor-pump unit (21) is connected via the hydraulic unit (15) to a plurality of fluid outlets for a first, a second and a third partial volume flow (20', 20'', 20'''), which for cooling and / or heating and / or lubrication are arranged at least on the stator (5) of an electric drive machine (2),and / or the rotor (3) of the electric drive machine (2) and / or the transmission (10), wherein the arrangement (1) comprises a heat exchanger (14), and wherein the first partial volume flow (20') is not connected to the heat exchanger (14), and wherein the direction of rotation and the pressure level of the motor-pump unit (21) can be adjusted via an electrical control unit and three different operating modes can be set depending on the direction of rotation and the pressure level. [2] Arrangement (1) according to claim 1, characterized by that the first partial volume flow (20') is assigned to the inlet of the gearbox (10), the second partial volume flow (20'') is assigned to the inlet of the rotor (3) and the third partial volume flow (20''') is assigned to the inlet of the stator (5). [3] Arrangement (1) according to claim 2, characterized bythat the hydraulic unit (15) has a shuttle valve (31) connected downstream in the flow path of the motor-pump unit (21) and a subsequent hydraulically controllable valve, preferably a 3 / 2-way valve, wherein the 3 / 2-way valve is adjustable from a first position to a second position via a control line and a control pressure. [4] Arrangement (1) according to claim 2, characterized by that the hydraulic unit (15) comprises only check valves (43, 44). [5] Arrangement (1) according to one of the preceding claims, characterized by that the first partial volume flow (20') is formed by means of a fluid line (16) in which a check valve (39) and an orifice (38b) are arranged. [6] Arrangement (1) according to one of the preceding claims, characterized bythat in the first position of the 3 / 2-way valve (32) the volume flow from the motor-pump unit (21) is connected to the heat exchanger (14) via a fluid line (34) and that the outlet of the heat exchanger (14) is designed as a fluid line (17) which branches into the second and third partial volume flow (20'', 20'''), wherein the third partial volume flow (20'''') runs directly as an inlet to the stator (5) and wherein the second partial volume flow is guided to the rotor (3) via a hydraulically controllable check valve (36). [7] Arrangement (1) according to one of the preceding claims, characterized bythat in the first operating mode, the pump speed of the motor-pump unit (21) is operated in the first clockwise direction of rotation with a low pressure level and the entire volume flow (40) flows via the shuttle valve (31) and the 3 / 2-way valve in the first position, the fluid line 24 and the heat exchanger (14) for cooling and lubricating the stator (5) as a third partial volume flow (20'''), and wherein the inlet to the rotor (3) and the gear (10) are blocked. [8] Arrangement according to one of claims 1-6, characterized bythat in the second operating mode the pump speed of the motor-pump unit (21) is operated in the first direction of rotation clockwise with a high pressure level and the volume flow (41) for actively cooling the gear (10), the rotor (3) and the stator (5) is guided via the 3 / 2-way valve in its first position, the heat exchanger (14) and only after the heat exchanger (14) is a division into the first, second and third partial volume flows (20, 20'', 20''') carried out, wherein the check valve (36) is in the unlocked position due to the high pressure level and after the check valve (36) a division of the volume flow into the first and second partial volume flows takes place via a fluid line. [9] Arrangement according to one of claims 1-6, characterized bythat in the third operating mode, the pump speed of the motor-pump unit (21) is operated in the second direction of rotation in the counterclockwise direction with a low pressure level and the entire volume flow (40) flows via the shuttle valve (31) and the 3 / 2-way valve in the second position and is divided into a first portion which flows via the fluid line (24) and the heat exchanger (14) for cooling and lubricating the stator (5) as a third partial volume flow (20'''), wherein the inlet to the rotor (3) is blocked and a second portion, starting from the 3 / 2-way valve (32), is fed directly via the fluid line (16) as a first partial volume flow (20') with a high feed temperature to the gearbox (10) for lubrication. [10] Method for the demand-based distribution and adjustment of flow temperatures of cooling / lubricating oil flows in electric traction drives with an arrangement (1) according to one of the preceding claims, characterized bythat three different operating modes can be set depending on the operation of the motor-pump unit (21) in a first direction of rotation or an opposite second direction of rotation and the setting of the pressure level, wherein a first and / or a second and / or a third partial volume flow (20, 20'', 20''') with the same or different flow temperatures can be set depending on the operating modes. [11] The method of claim 10, wherein the three operating modes represent an efficiency mode with optimized energy management, a maximum conduction mode, and a moderate driving mode with reduced cooling of only the windings of the stator. [12] Method according to claim 11, wherein the switching between the operating modes is carried out on the basis of the parameters oil temperature, pump power, power and speed of the electric machine. [13] Method according to claim 10, characterized bythat in the first operating mode, the pump speed of the motor-pump unit (21) is operated in the first clockwise direction of rotation at a low pressure level, whereby active cooling of the stator (5) is achieved exclusively via the third partial volume flow (20''') [14] Method according to claim 10, characterized by that in the second operating mode, the pump speed of the motor-pump unit (21) is operated in the first clockwise direction of rotation at a high pressure level, whereby active cooling of the gear (10), the rotor (3) and the stator (2) is achieved via the first, second and third partial volume flows (20', 20'', 20''') with the same flow temperatures. [15] Method according to claim 10, characterized bythat in the third operating mode, the pump speed of the motor-pump unit (21) is operated in the second direction of rotation counterclockwise with a low pressure level, whereby active cooling of the stator (5) via the third partial volume flow (20''') with a low flow temperature, and lubrication of the gear (10) via the first partial volume flow with a higher flow temperature is achieved.

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